This hails from Reno, one of the more notable personalities I know in the FG community, as well as a regular poster on NeoGAF and SRK.
According to an arcade operator friend of mine (later confirmed by another source), Sega will be announcing a new 2D fighter at AOU2009 on Feb 28 - 29. The game will be another Sega/Arc Systems collaboration though, so I don't know how much excitement this is going to generate.
Anyway, expect an announcement at AOU for the game. I don't think it'll be HnK2, but you never know...
Now, while he may be doubtful about a sequel to HnK, I personally think it may more likely than one might be inclined to think.
As it stands right now, there's really only two reasons that ASW and Sega would have just cause to continue to deal with each other, in spite of splitting up a couple years back. And those two are Hnk, and well, Guilty Gear X/XX.
Possibly the ONLY reason I can't imagine GG being a part of this, would be because this would do more to interfere with ASW's marketing of their new flagship, HD-marvel, BlazBlue. It's a rule of thumb in arcades that many devs, including Capcom and SNK, have had to learn the hard way: it's NOT good practice to try and market too many of your products at the same time. Especially when you're trying your damndest to make a good impression with something new and untested vs. an old flame that's tried and true.
So, for that reason alone, I could not see a GGXXX, yet. That would only do more to hurt BlazBlue, and I'm certain ASW doesn't want that.
That said, it leaves the window open for either a) HnK 2 or b) something else entirely. Any body who remembers my former SN will probably have a good idea of what I'm personally rooting for, but we shall see!
In any case...
http://www.youtube.com/watch?v=Ya8XrGL9IU8&feature=channel_page